SU930757A1 - Cored induction furnace - Google Patents

Description

(54) INDUCTION DUCT FURNACE

i

The invention relates to electrical engineering, and more specifically to induction channel furnaces.

Intensification of the heat and mass transfer between the bath and the induction unit by creating a transit flow through the channels reduces the metal overheating in the channels and also improves the capabilities of the channel furnace as a metallurgical unit. As a result, it is possible to substantially; This increases the power of induction units, extends the service life of their lining and increases the productivity of the channel furnace.

The known indiz shchgonny channel furnace with double induction unit, in which the method of melting is carried out, providing -. The creation of a continuous flow of metal through the channels 1.

However, the intensity of metal movement is insufficient: to ensure a high degree of heat and mass transfer.

Closest to the offer is a 1-channel duct furnace containing

the bath and the double induction unit located under it, made in the form of a channel system consisting of bottom, side and center channels connected to the bath, covered by magnetic inductor with inducers, with a dielectric partition 2 installed in the bottom of the central channel.

/ However, the known channel furnace inherent

10 insufficient intensity of heat and mass transfer and for a number of technological processes not the optimal direction of metal flow. For example, when treating a melt with any active surface flux, in order to avoid corroding the furnace lining, the flux can be placed on the surface of the melt above the mouth of the central channel, limited to the refractory glass recessed into the melt. Then, if the metal is ejected from

Claims (1)

20 central channel, i.e. if the melt through flow has the opposite / direction, the processing efficiency will increase dramatically. 39 The purpose of the invention - heat and mass transfer. The goal is achieved by the fact that the section & drain of the central channel above the horizontal axis of the inductors is 1.2-2 times the length of the same sections of the side channels, and the indicated partition is filled with a width equal to the channel width. FIG. 1 shows the furnace design; in fig. 2 is a graph showing the change in metal overheating along the length of the furnace. The furnace consists of baths I and a dual induction unit 2 attached to it, in the hearth 3 of which central 4 is made, side 5 are connected to the bottom 6 channels connecting them. A diesel generator, the partition 7 is placed along the symmetry axis of the unit. Moreover, the lower end of the partition directly adjacent to the bottom of the lower channel and completely overlaps it. The section of the central channel located above the horizontal axis of the inductors is 1.2–2 times longer than the similar sections of the side channels. The furnace works as follows. When connecting inductors with phase shift magnetic flux inductors equal to; zero, the currents induced in the central channel are oppositely directed, and the total current in it is also zero. However availability. a baffle that completely covers the lower channel causes the current to bend around it, entering the central channel. At the site of current bending from its interaction with its own magnetic field, electromagnetic forces arise that are directed along the external normal to the current lines and have components along the central channel in the direction of the furnace bath. The same forces arise in the upper part of the central channel. The elongation of the central channel as compared with the lateral channels also creates a favorable geometry for hydrodynamic vortices formed above the mouth of the central channel. It prevents the return flows of the metal into the central channel, ZTM1 causes uneven distribution of current density in the mouths of the side channels and thus reduces the intensity of eddies arising there, opposing the main transit flow direction, intensifies the movement of the metal in the whole bath volume. Thus, there is an intense movement of the meuall through the channels with the release of superheated metal from the central channel to the bath and flowing through the relatively cold metal into the side channels. FIG. Figure 2 shows the change in overheating of the metal (relative to the temperature of the furnace bath) along the length of the furnace channel without lengthening the central channel (curve 1) and for the furnace with extension of the central core (curve 2). The origin of the coordinates corresponds to the cut-off side channel. As follows from the curves, in both cases there is a good transit metal flow. However, in the first inlet to the side channel, there is already an overheating of 16 ° C. This means that the hot stream from the central channel does not spread deeply into the bath, but directly unfolds to the mouths of the side channels. In this case, the maximum overheating of the metal in the channel is 33 - 35 ° C, the calculated rate of transit flow from the heat balance equation is 2 cm / s. In the second case, when the central channel is extended, the stream from it spreads far into the bath (Fig. 1) and at the exit to the side channel the temperature of the metal is even 2--3 ° C lower than in the bath, with the same active power of the furnace. The transit flow rate in this case is 2.65 cm / s, and the maximum overheating of the metal in the channel decreases to 12 ° C, i.e. almost three times. TaKHJsl way, the implementation of a known method of melting in the induction furnace of the proposed design allows to obtain a transit flow of metal of the opposite direction. At the same time, with the same channel current, the rate of transit flow increases approximately four times. Improving the heat and mass transfer between the metal in the furnace bath and the induction unit allows to increase the service life of the lining by reducing the temperature of the metal in the channels, increasing the productivity of the furnace by 20-40%. The presence of an intense transit flow exiting the central channel allows the use of the proposed design for the efficient performance of various technological operations associated with the implementation of reactions taking place at the interface between the liquid and solid phases. An Induction Channel Furnace, comprising a bath and a double induction unit located under it, made in the form of a channel system consisting of a bottom, side and central, connected to the bath, covered by inducers with a mains, and in the bottom of the central channel there is a dielectric partition, characterized in that, in order to intensify heat and mass transfer.